It is common to employ annular apparatus, including an antenna, for electronically transmitting tire or wheel identification or other data at radio frequency. The apparatus includes a radio-frequency tag, or transponder, comprising an integrated circuit chip having data capacity at least sufficient to retain identification information for the tire or wheel. Other data, such as the inflation pressure of the tire or the temperature of the tire or wheel at the transponder location, can be transmitted by the transponder along with the identification data.
The annular antenna is tire-mounted and transmits, at radio frequencies, data from the transponder to a reader mounted on the wheel assembly. The antenna and transponder may be incorporated into a tire during “pre-cure” manufacture of the tire. The integrity of the connection between the tire and antenna is greatly enhanced by a pre-cure assembly procedure. In practice, however, it is very difficult to do this. Both radial ply and bias ply tires undergo a substantial diametric enlargement during the course of manufacture. Bias ply tires are expanded diametrically when inserted into a curing press, which typically has a bladder that forces the green tire into the toroidal shape of the mold enclosing it. Radial ply tires undergo diametric expansion during the tire building or shaping process and a further diametric expansion during the course of curing. An annular antenna and the electronic tag associated therewith built into the tire in a pre-cure process, therefore, must endure significant strain that can result in component failure. The electronic tag and the connection between the tag and the antenna, in particular, is vulnerable to damage from the forces imposed from pre-cure assembly to tire.
To avoid damaging the electronic tag or the connection between the tag and the annular antenna during the curing procedure, an alternative approach is to assemble the tag and antenna into a separate annular unit for post-cure attachment to the tire. An automated apparatus and method for attaching an annular transponder unit to an annular tire surface is proposed that utilizes end-of-arm tooling to progressively attach the annular unit to the tire section by section. To install the annular antenna ring, the transponder housing is held by an external robotic arm and brought into contact with a small patch of adhesive previously applied to the tire. The robotic arm releases the transponder housing and a relative rotation between the tire and the robotic end-of-arm tooling is established, either through rotation of the tire or the tooling or both. The annular antenna is guided section by section through the tooling and applied by adhesive to the tire surface.
While working well, it is important that the annular ring not move radially relative to the tire as the annular unit is attached. Such movement can cause the annular ring to become dislocated due to the friction between the annular antenna ring and the end-of-arm tooling guide mechanism. Dislocation of the annular transponder unit from its intended position on the target annular tire surface can cause a malfunction or degradation in tire monitoring system performance or necessitate repeating the procedure for attaching the annular transponder unit to the tire.
Accordingly, there is a need for an apparatus and method of fixing an annular transponder unit against an annular tire surface while relative rotation between the tire and application tooling is established. Such an apparatus should fix a designated portion of the annular unit against the tire in a manner that does not interfere with a section by section attachment of the annular transponder unit to the tire by end-of-arm robotic tooling. Such a procedure should further ensure the functional safety of the electronics and maintain a secure electrical connection between the antenna and tag electronics. It is further desirable that any such apparatus and method for fixing an annular transponder unit to a tire during an attachment sequence have minimal labor content in order to reduce human error and the cost of manufacture. Finally, such a procedure ideally should synchronize seamlessly with end of arm application tooling in a manner that minimizes cycle time.